S T l/ D I A G E O M O RP H O L O G I C A C A R PATH O -BA L CA N I CA VOL. Xxxll KRAKÓW 1998 F'L ISSN 008l-6434 MILOŚ STANKOVIANSKY (BRATISIAVA), RUDOLF MIDRIAK (ZVOLEN) THE RECENT AND PRESENT-DAY GEOMORPHIC PROCESSES IN SLOVAK CARPATHIANS STATE OF THE ART REVIEW INTRODUCTION The aim of the contribution is to characterize the state of the art of investigation of the recent and present-day geomorphic processes taking part in shaping the relief of the Slovak Carpathians. Attention is paid to the research rea]ized in the period of the last 10-15 years. The results of older investigations of selected groups of processes are summarized in an exhaustive manner in well known book monographs by Nemćok (1982) on landslides, Zachar (1982) on soil erosion and Mi d ri ak (1983) on geomorphic processes operating in high mountains. The trends of investigation of the geomorphic processes in the Slovak scientific, research and pedagogic institutions were summed up by Stankoviansky (1983,1984a). The contribution is divided into two parts, characterizing the operation of geomorphic processes in two basic altitudinal climatic morphogenetic systems, identified in the Carpathians by Kotarba and Starkel (1972). These are lower and much more extensive temperate forest system and the higher but little extensive ciyonival system. Their boundary is represented in fact by the upper timber line which is identical here rough]y with the contour line of 1,500 m a.s.l. The above morphogenetic systems are characteristic by markedly different geo-ecological conditions resulting also in differences in the occurrence and course of the geomorphic processes. In the sense of the classification of exogenic geomorphic processes by Stankoviansky (1983), the investigation of the processes in the territory of the Slovak Carpathians was focused above all on the gravitational, wa- ter-induced (namely runoff, fluvial, standing water), cryogenic, nival and eolian processes. 70 THE RECENT AND PRESENT-DAY GEOMORPHIC PROCESSES IN TEMPERATE FOREST MORPHOGENETIC SYSTEM This pait is devoted to the results of study of the recent and present-day geomorphic processes and landforms shaped by these processes in the given morphogenetic system. From among the above mentioned groups of geomorphic processes, attention is paid mainly to the operation of gravitational and water- induced processes. The gravitational processes represent the most serious geomorphic hazard in Slovakia. The partial gravitational processes as creep, sliding, f]owing and falling result in the creation of the slope deformations as creep deformations, Iandslides, slope flows and rock falls (M al g o t et al. ]994). It was not possible to distinguish the o]der gravitational deformations from the recent and present- day ones in the contribution. Nemćok (1982) quotes the total 9,194 slope failures in Slovakia, affecting roughly 1,500 km2, i.e. approximately 3°/o of its territory. By Modlitba and Klukanovó (1996) 4,447 new localities were registered during another stage of systematic investigation of gravitational defor- mations jn the 1980s. The research found out that the regional extent of the gravitational deformations depends on the geologic structure, geomorphic and climatic conditions. The most affected areas are that built by flysch rocks, the intermountain basins and young volcanic mountains. Specific types of slope failures originated in the core mountains, above all in high ones, built by the crystalline and Mesozoic sedimentary rocks (Malgot and Baliak 1996). The gravitational deformations damage the forests, meadows, pastures and arable land. Approximately 90% of new deformations originate by reactivation of older ones due to negative anthropic interventions (Malgot and Baliak 1993). In connection with high degree of hazard of gravitational processes, the sys- tematic long-term monitoring of their actjvjty is realized, focused on selected localities of primary economic interest (Wagner et al.1996b, 1997). The most complex publication on gravitational deformations is that of w a g n e r et al. (1996a), summarizing the present results of research of these phenomena from the Slovakia wide viewpoint and introducing selected examp]es of contem- porary regional investigations. From among other numerous regional works on this topic we present only the ones conceming the flysch regions (e.g. Kovócikovó et al.1989, Kovśćik and Ondróśik 1991, Kovóćik 1992, Harćar 1993) and the volcanic mountains (e.g. Dzurovcin 1990, Harćór and Krippel 1994). The study of the water-induced geomorphic processes was focused above all on the runoff and fluvial processes, as well as on the processes of standjng waters. Under "runoff processes", the geomorphic processes initiated by surface runoff, i.e. by water flowing down the slope surface during extreme rainfalls and snow melt (cf. Stankoviansky 1995,1997b), named by the pedologists "water erosion", are meant. The runoff processes were studied in disparate landscape types (woodland, farmland) but also in mixed woodland-farmland 71 types in the framework of drainage basins or parts of mountains. Various approaches were used namely the measurement of the rate of the present-day processes, mapping of their spatial distribution, assessment of geomorphic effect of present-day and recent processes, as well as the evaluation of trans- formations in operation of the processes due to land use changes. The measurements of the rate of runoff processes using a deluometric method were realized exclusively in woodland, namely in the spruce and beech ecosystems, partially also in the fir, pine, larch, oak and hornbeam ecosystems (Midriak 1993b). Absolute and relative soil losses were distinguished while the first case represents the actual removal of material to hydrographical network, the second its redistribution limited to the slope. The measured values of the absolute soil losses in woodland in Slovakia are in fact very low, they reach 18 kg/ha/year in average in coniferous forest and 24 kg/ha/year in deciduous forest. However, these values fluctuate in particular localities, they range from 1 to 61 kg/ha/year. The lowest absolute soil losses are typical for the fir and spruce forests, the average soil losses for the beech forests and above the average for the oak and pine forests. The relative soil losses are represented by the redistribution of the inorganic as well as organic material, while the displacement of inorganic matter is more significant. The annual redistribution of inorganic material reaches 8-891 kg/ha (109-323 kg/ha in average), depending on the specific conditions of particular stand. The amount of redistributed organic particles is 15-544 kg/ha/year (132-255 kg/ha/year in average). In general, the presented results testibr the high anti-erosional effectiveness of forests. However, this function of forest is on many places markedly weakened, namely by the large scale forest clearance, incorrect skidding technologies, construction of forest unpaved roads, ski run tracks and ski lifts (Midriak 1988). The influence of anthropic activities on the runoff processes in woodland was studied in the locality Komamik situated in the Laborec Upland, built by flysch rocks, covered by mixed fir-beach forest and in the locality Biely Vóh in the part of the Kozie chrbty Mts, built by carbonate rocks, covered by spruce forest (Midriak 1989, 1994). In the first case, the absolute soil losses are 13-20 kg/ha/year, the relative losses are 333-1,000 kg/ha/year, in the second case it is 22-51 kg/ha/year and 423-688 kg/ha/year respectively. The highest values in both localities were associated with clear-cut areas (M i driak 1989). The measurements of the rate of runoff processes were realized also in the East Carpathian Biosphere Reserve, built by flysch rocks (M i dri ak 1995a,1995b). The measured values of the absolute soil losses by areal runoff processes are relatively low (16*1 kg/ha/year), but the total losses (i.e. absolute plus relative ones) on clear-cut areas reach up to 1,570 kg/ha/year. Much higher soil losses are initiated by the linear runoff processes controlled by tractor wheel tracks, logging tracks, forest roads, etc. Such soil losses are almost 100-times higher than the losses initiated by areal erosion (4.4-14 m3ma/year). The average removal from one meter of length of unpaved skidding roads due to both the mechanica] 72 scraping of me road surface by logged trees and the successive operation of concentrated flow erosion, ranges from 0.13 to 0.61 m3AJear (Midriak 1995b). Contrary to the woodland, the runoff processes in farmland were studied from the viewpoint of their geomorphic effect, under which above all tiie geometric transfomations of relief and changes in operation of the given processes are meant. The research was focused on the intensively cultivated areas of the Myjava Hjll Land, mainly in the Jablonka Catchment (Fig. 1). An immediate, operaŁive effect of the particular and documented erosion-accumulation events, as well as the medium-tenn to long-term effect of sequence of anonymous consecutive events during the period of anthropically influenced re]ief shaping were distinguished (Stankoviansky 1998). The immediate geomorphic effect of areal and linear runoff processes was studied on the basis of successive de{ajled map documen- tation of manifestations of single events, either extreme rainfalls (S t a n k o v i a n s k y 1997d) or snow melt (Stankoviansky 1995), namely for the purpose of un- derstanding the regulations of spatial distribution of the rills and ephemeral gullies in relation to relief, land use and ti]Iage practices (Figs. 2 and 3, Photo 1). The eva]uation of long-term geomorphic effect of relief-forming processes in the territory of the Myjava Hill Land resulted in the identification of the stages of its relief shaping in the Holocene with characteristic sets of processes and [heir geomorphic manifestations (Stankoviansky 1994a).